New oxygen isotope evidence for long-term Cretaceous climatic change in the Southern Hemisphere

Clarke, Leon J.; Jenkyns, Hugh C.

doi:10.1130/0091-7613(1999)027<0699:noiefl>2.3.co;2

Cited by 378 publications

(219 citation statements)

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“…This warm peak may have also been the trigger for the expansion of the angiosperms in the Antarctic, represented by a marked increased abundance of angiosperm pollen in Turonian sediments (Keating et al, 1992). On a global scale this corresponds to the Cretaceous thermal maximum, from about 100-80 Ma, reported from many sites (e.g., Clark and Jenkyns, 1999;Huber et al, 2002), and possibly attributed to rising atmospheric CO 2 levels due to a tectonically driven oceanographic event in the opening of the equatorial Atlantic gateway (Poulsen et al, 2003).…”

Section: Francis Figmentioning

confidence: 99%

100 Million Years of Antarctic Climate Evolution: Evidence from Fossil Plants

Francis¹,

Ashworth²,

Cantrill³

et al. 2007

Open-File Report

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Section: Francis Figmentioning

confidence: 99%

100 Million Years of Antarctic Climate Evolution: Evidence from Fossil Plants

Francis¹,

Ashworth²,

Cantrill³

et al. 2007

Open-File Report

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“…However, the magnitude of the temperature change based on bulk-rock oxygen-isotopes is difficult to constrain because of the diagenetic alteration of fossil carbonate (Gale and Christensen, 1996;Wilson et al, 2002;Voigt et al, 2004) and the uncertainty with regards to the isotopic composition of the Cretaceous seawater Keller and Pardo, 2004;Voigt et al, 2004;Kuhn et al, 2005). The CenomanianeTuronian transition corresponds to the onset of the interval of peak Cretaceous warmth, which reached its thermal maximum in the Late Turonian (Clarke and Jenkyns, 1999;Wilson et al, 2002). The decreasing trend in d…”

Section: Paleoenvironmental Conditions In the Helvetic Realm During Omentioning

confidence: 99%

Evidence for oxic conditions during oceanic anoxic event 2 in the northern Tethyan pelagic realm

Westermann

Caron

Fiet

et al. 2010

Cretaceous Research

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Upper Cenomanian pelagic sediments from the northern Alpine Helvetic fold-and-thrust belt (northern Tethyan margin) coeval with Oceanic Anoxic Event (OAE) 2 are characterized by the temporal persistence of micrite sedimentation and lack of organic carbon-rich layers. We studied an expanded section in the Chrummflueschlucht (east of Euthal, Switzerland), which encompasses the OAE 2 time interval. In order to identify the paleoceanographic and paleoenvironmental conditions during OAE 2 in this part of the northern Tethyan margin, and more specifically to trace eventual changes in nutrient levels and oxic conditions, we investigated the biostratigraphy (planktonic foraminifera), the bulk-rock mineralogy, and measured stable carbon-and oxygen-isotopes, total phosphorus (P) and redox-sensitive trace-element (RSTE) contents.We were able to determine e with some remaining uncertainties e the different planktonic foraminiferal biozones characteristic of the CenomanianeTuronian boundary interval (Rotalipora cushmani, Whiteinella archaeocretacea and Helvetoglobotruncana helvetica zones). In the lower part of the section (R.cushmani total range zone), the bulk-rock d 13 C record shows a long-term increase. Within sediments attributed to the W. archaeocretacea partial range zone, d13 C values reach a maximum of 3.3& (peak "a").In the following the values decrease and increase again to arrive at a plateau with high d13 C values of around 3.1&, which ends with a peak of 3.3& (peak "c"). At the top of the section, in sediments belonging to the H. helvetica total range zone, d13 C values decrease to post-OAE values of around 2.2&.The last occurrence of R. cushmani is observed just above the positive d 13 C shift characterizing OAE 2. P contents display small variations along the section with a long-term decreasing trend towards the top. Before the OAE 2 interval, P values show higher values and relatively good covariation with detrital input, indicating higher nutrient input before OAE 2. In sediments corresponding to the onset of the d 13 C positive excursion, P content is marked by a sharp peak probably linked to a slowdown in sedimentation rates and/or the presence of a small hiatus, as is shown by the presence of glauconite and phosphatic grains. In the interval corresponding to OAE 2, P values remain low and increase slightly at the end of the positive shift in the d 13 C record (in the H. helvetica total range zone). The average contents of RSTE (U, V, As, Co, Mo and Mn) remain low throughout the section and appreciable RSTE enrichments have not been observed for the sedimentary interval corresponding to OAE 2. No correlation is observed with stratigraphic trends in RSTE contents in organic-rich deeper-water sections. The presence of double-keeled planktonic foraminifera species during most of the Cenomanian/Turonian boundary event is another evidence of relatively well-oxygenated conditions in this part of the northern Tethyan outer shelf.Our results show that the Chrummflueschlucht section corresponds to one of the most...

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“…In addition, whereas the Aptian Sr-isotope excursion implies a relative increase in hydrothermal activity that is 70 percent larger than the Cenomanian-Turonian ( fig. 8), a new ␦ 18 O record from Exmouth Plateau off the coast of Australia suggests that the Cenomanian-Turonian was significantly warmer than the Aptian (Clarke and Jenkyns, 1999).…”

mentioning

confidence: 99%

“…O values from Cretaceous calcareous fine-fraction and bulk sediments from the Exmouth Plateau off Australia, suggesting that the data from the English Chalk reflect a global pattern of paleotemperature change (Clarke and Jenkyns, 1999). Although the precise role of temperature in controlling weathering rates is debated (Ruddiman, 1997), global warming should, if anything, increase the rate and/or intensity of chemical weathering (White and Blum, 1995).…”

mentioning

confidence: 99%

Seawater strontium isotopes, oceanic anoxic events, and seafloor hydrothermal activity in the Jurassic and Cretaceous

Jones¹

2001

American Journal of Science

460

323

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ABSTRACT. There were three negative seawater strontium-isotope excursions (shifts to lower 87 Sr/ 86Sr values) during the Jurassic and Cretaceous that were of relatively short duration (5-13 my) and showed a relatively quick recovery to pre-excursion 87 Sr/ 86 Sr ratios. These excursions occurred in the Pliensbachian-Toarcian (Early Jurassic), Aptian-Albian, and Cenomanian-Santonian (Early and Late Cretaceous respectively). Each excursion coincided closely in time with an Oceanic Anoxic Event (OAE) marked by sediments unusually rich in organic carbon. The Jurassic OAE occurred at the end of the strontium-isotope excursion, whereas the two Cretaceous OAEs occurred at the onset of the accompanying strontium-isotope excursions.The possible causes of these excursions were evaluated by successively examining the changes in the riverine strontium fluxes, riverine 87 Sr/ 86 Sr ratios, or hydrothermal strontium fluxes required to produce each excursion. A range of seawater strontium budgets was used to encompass the uncertainties in modern and ancient cycles. To produce the excursions, we calculate that the riverine strontium fluxes would have had to decrease by 6 to 15 percent or the fluvial 87 Sr/ 86 Sr ratios by 0.00019 to 0.00046. The uncertainties largely stem from the assumed magnitude of the hydrothermal strontium flux at the onset of each excursion. Alternatively, increases in sea-floor hydrothermal activity of 7 to 104 percent could also have produced the strontium-isotope excursions. This large range is due mostly to uncertainties in the relative flux of strontium from axial high-temperature hydrothermal systems and low-temperature off-axis systems. Only a small portion of this range stems from uncertainties in the riverine strontium terms.The possible causes of the excursions were further evaluated by examining several geologic factors that could have affected riverine strontium, including climate change, sealevel, and the eruption of flood basalts. We conclude that neither variations in riverine strontium fluxes nor in 87 Sr/ 86 Sr ratios is the likely cause of the strontiumisotope excursions. The most probable explanation is increased rates of hydrothermal activity related to increased ocean-crust production at the mid-ocean ridges.The close correlation in time between the strontium-isotope excursions and the major Oceanic Anoxic Events (OAEs) is compatible with a causal linkage. We propose that increased ocean-crust production led to enhanced CO 2 outgassing and global warming, which in turn led to several processes that acted to make surface ocean waters more productive. However, because OAEs did not occur throughout the proposed periods of enhanced hydrothermal activity, it appears that these processes only preconditioned the oceans for the OAEs: sealevel rise may have been the final trigger. This model explains why all three OAEs did not occur at the same time relative to the onset of excess hydrothermal activity and why OAEs are not associated with every sealevel rise documented in the stratigraphic re...

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New oxygen isotope evidence for long-term Cretaceous climatic change in the Southern Hemisphere

Cited by 378 publications

References 1 publication

100 Million Years of Antarctic Climate Evolution: Evidence from Fossil Plants

100 Million Years of Antarctic Climate Evolution: Evidence from Fossil Plants

Evidence for oxic conditions during oceanic anoxic event 2 in the northern Tethyan pelagic realm

Seawater strontium isotopes, oceanic anoxic events, and seafloor hydrothermal activity in the Jurassic and Cretaceous

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